1. Field
Aspects of embodiments of the present invention relate to a light emitting display device.
2. Description of the Prior Art
Among light emitting display devices, an organic light emitting display device is a self-luminous display device which has the characteristics of a relatively wide viewing angle, superior contrast, and high response speed, and thus has been noticed as the next-generation display device.
An organic light emitting display device has a light emitting layer that is made of an organic light emitting material arranged between an anode electrode and a cathode electrode. If anode and cathode voltages are applied to these electrodes, respectively, holes that are injected from the anode electrode move to the light emitting layer through a hole injection layer and a hole transport layer, and electrons move to the light emitting layer through an electron injection layer and an electron transport layer. In the light emitting layer, the electrons and the holes are recombined, and through this recombination, excitons are generated. As the generated excitons are transited from an excited state to a ground state, the light emitting layer emits light to display an image thereon.
The organic light emitting display device may include a pixel defining layer having an opening for exposing the anode electrode that is formed on each of pixels, and a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode electrode are formed on the anode electrode that is exposed through the opening of the pixel defining layer. Among them, the light emitting layer may be formed in various methods, and one of such methods is a deposition method. Recently, as the deposition method, a small mask scanning deposition method, in which a deposition process can be performed in small-scale equipment, has been widely used.
In the case of forming the light emitting layer of the organic light emitting display device using the small mask scanning deposition method, the light emitting layer can be formed by arranging a substrate and a mask that is smaller than the substrate to be spaced apart from each other and depositing an organic light emitting material on the substrate while moving the mask and the substrate relatively to each other.
The above information disclosed in this Background section is only to enhance the understanding of the background of the invention, and therefore it may contain information that does not constitute prior art.